Abstract:

Against the background of ecological protection and high-quality development in the Yellow River Basin, the water ecosystem service functions of the Liupan Mountain area, which is known as the wet island, have become increasingly critical to the arid Loess Plateau. Thus, the study aimed to establish an assessment method for the supply and demand of ecosystem water-yielding services suitable for mountainous regions. This method, combined with the Integrated Valuation of Ecosystem Services and Trade-offs model and a supply-demand matching index, was used to systematically evaluate the multidimensional differentiation characteristics of the supply and demand of ecosystem water-yielding services in this region across temporal and spatial dimensions. The results illustrated that in the previous three decades, the supply and demand of ecosystem water-yielding services in the Liupan Mountain area followed a pattern of first decreasing then increasing. The southeastern mountainous area experienced the most significant change in supply (13.1%), while the northern mountainous area experienced the largest change in demand (-37.1%). The study identified mountainous regions situated above 2000 m as supply zones for ecosystem water-yielding services and areas characterized by high degrees of supply-demand matching. Conversely, areas below 2000 m were considered predominantly demand zones. After the year 2000, high-demand areas shifted from the north to the southeastern and southwestern mountainous regions, thus forming a spatiotemporal distribution pattern of supply-demand matching degrees characterized by high, moderate, and low levels in the north, southwest, and southeast, respectively. In conclusion, the supply and demand of ecosystem water-yielding services in the Liupan Mountain area exhibited a multidimensional uneven distribution pattern across spatiotemporal dimensions and vertical zones. Over time and with increasing altitude, the matching degrees of supply and demand in the northern mountainous areas displayed an upward trend before the year 2000 but a downward trend in the southwestern and southeastern mountainous areas. Conversely, after the year 2000, the matching degree in the northern mountainous areas decreased, whereas that in the southwestern and southeastern areas increased. The findings revealed the spatial differentiation law of the supply-demand relationship of water resources in the Liupan Mountain area, which provides a scientific foundation for the optimal allocation of water resources in arid mountainous regions.

Key words: InVEST model, ecosystem services, supply-demand matching, spatiotemporal differentiation, Liupan Mountain area